When updating with the refresh button in BP, may also happen with auto update, it doesn't show an icon in the notification bar, but when you pull down the shade you can see the status. This is when the Synching Local Changes status is present. Once reaching the actual feed refresh the notification icon appears.
In previous non-4.X I recall this feature working where the downloading notification appeared immediately.
There is also no animation of the update button in the client so you can't see if it is actually updating or not when pressing the button.
Sony Xperia Z1 compact, KitKat 4.4.4, BP 4.0.31